Very recently, three China invention patents on the preparation techniques of high performance materials, named “A Preparation Method of Large-scaled Bulk Nanostructured Fe-C Alloys”, "A Preparation Method of Bulk Fe-B Soft Magnetic Materials”, and “A Preparation Method of Ni-Al Intermetallic Compound-Based High Temperature Self-Lubricating Composite Materials”, have been granted in the State Key Laboratory of Solid Lubrication of the Lanzhou Institute of Chemical Physics (LICP) of the CAS.
Fe-C alloys, also called carbon steel, are a kind of the most widely used structural materials. However, the relatively low strength restricted the expansion of engineering applications. Using Fe2O3, Al and carbon powders as raw materials, researchers have successfully prepared large-scaled bulk nanostructured Fe-C alloy by a combustion synthesis melt technique. The material exhibits excellent mechanical properties. Bending strength reaches as high as 1500-1800 MPa, and compressive yield strength and strain are 1300 MPa and 20%, respectively. The technique is straightforward and has the advantages of low energy consumption, short processing time and low cost. Compared with alloy strengthening method, the nano-scaled strengthening technique not only significantly improves strength of metal materials but also reduces the use of noble metals and rare metals.
By the combustion synthesis melt technique, researchers have also produced bulk Fe-B soft magnetic materials with superior soft magnetic and mechanical properties. With the advantages of high magnetic permeability and magnetic induction, low coercivity and magnetic loss, the material can be applied in micro controller units, electrical motors, transformers, magnetic recorders and magnetic heads. The technique has expanded the ways to prepare nano-materials with excellent soft magnetic properties.
At temperatures above~350 ℃ and, especially, in oxidizing environments, conventional liquid lubricants, and conventional polymer based self-lubricating material degrade rapidly. However, some moving parts are operated at the temperatures of 800-1000℃. The wear-resistance and lubricity of the moving parts under such high temperature are the key factors to influence the whole system performance, reliability and service life. The topic belongs to a hotspot in the field of tribological material research.
In view of this, researchers have prepared Ni-Al intermetallics-based high temperature self-lubricating composite materials by powder metallurgy technology. The materials exhibit excellent continuous self-lubricity, wear resistance and mechanical property from room temperature to 1000℃.
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